IMac 27 "screen brightness hovering. I presumption this is a 2009 model he bought in November 2010. I am sure that this greater part is an LED display. I'm using the most recent OS X with Windows 7 64 bits. Stir in both OS. I was hoping the software updates that address this problem, either in the form of operating system updates, or updates of Boot Camp, but without success.
The condition is intermittent and erratic changes in the brightness setting, even when set at the highest levels, the screen shining step further than you can manually select maximum. I say step because it resemble a digital scheme that is software connected, not hardware. Seem to be a substance of maintaining steady brightness adjustment.